feat: Warn when loading deprecated files

lib/helpers/deprecation_helper.rb

@@ -1,12 +1,14 @@
 module DeprecationHelper
   def deprecate_method(old_method, new_method)
     define_method(old_method) do |*args, &block|
-      warn "Warning: `#{old_method}` is deprecated; use `#{new_method}` instead."
+      klass = is_a? Module
+      target = klass ? "#{self}." : "#{self.class}#"
+      warn "Warning: `#{target}#{old_method}` is deprecated and will be removed in version 6 of valid_email2; use `#{new_method}` instead."
       send(new_method, *args, &block)
     end
   end
 
   def deprecation_message(old_name, new_name)
-    warn "Warning: `#{old_name}` is deprecated; use `#{new_name}` instead."
+    warn "Warning: `#{old_name}` is deprecated and will be removed in version 6 of valid_email2; use `#{new_name}` instead."
   end
-end
+end

lib/valid_email2.rb

@@ -19,21 +19,33 @@ def disposable_emails
     end
 
     def deny_list
-      @deny_list ||= load_if_exists(DENY_LIST_FILE || BLACKLIST_FILE)
+      @deny_list ||= load_if_exists(DENY_LIST_FILE) ||
+        load_deprecated_if_exists(BLACKLIST_FILE) ||
+        Set.new
     end
-    alias_method :blacklist, :deny_list
     deprecate_method :blacklist, :deny_list
 
     def allow_list
-      @allow_list ||= load_if_exists(ALLOW_LIST_FILE || WHITELIST_FILE)
+      @allow_list ||= load_if_exists(ALLOW_LIST_FILE) ||
+        load_deprecated_if_exists(WHITELIST_FILE) ||
+        Set.new
     end
-    alias_method :whitelist, :allow_list
     deprecate_method :whitelist, :allow_list
 
     private
 
     def load_if_exists(path)
-      File.exist?(path) ? load_file(path) : Set.new
+      load_file(path) if File.exist?(path)
+    end
+
+    def load_deprecated_if_exists(path)
+      if File.exist?(path)
+        warn <<~WARN
+          Warning: The file `#{path}` used by valid_email2 is deprecated and won't be read in version 6 of valid_email2;
+          Rename the file to `#{path.gsub("blacklisted", "deny_listed").gsub("whitelisted", "allow_listed")}` instead."
+        WARN
+        load_file(path)
+      end
     end
 
     def load_file(path)

lib/valid_email2/address.rb

@@ -90,13 +90,11 @@ def disposable_mx_server?
     def allow_listed?
       domain_is_in?(ValidEmail2.allow_list)
     end
-    alias_method :whitelisted?, :allow_listed?
     deprecate_method :whitelisted?, :allow_listed?
 
     def deny_listed?
       valid? && domain_is_in?(ValidEmail2.deny_list)
     end
-    alias_method :blacklisted?, :deny_listed?
     deprecate_method :blacklisted?, :deny_listed?
 
     def valid_mx?